Sound box



H. Y. PRENDERGAST.

SOUND BOX.

APPLICATION FILED APR. 26. 1920.

Patented Mar. 21, 1922.

IIH H is wm A 1101mm HAROLD Y. PRENDERG-AST, OF BROOKLYN, NEW YORK.

SOUND BOX.

Specification of Letters Patent.

Patented Mar. 21, 19-22.

Application filed April 26, 1920. Serial No. 376,474.

is placed under tension in the assemblage ofthe box parts to exert a resilient holding effect upon the diaphragm edge. The hold 7 ing member operates as a sounding board and through its peculiar construction is spaced throughout its. full sounding area from the diaphragm.

I The object of the present invention is to provide .a sound box which entirely eliminates the necessity of resilient gaskets, as means whereby pressure may be exerted upon the diaphragm. to hold it in place, this being accomplished. in accordance with the present invention, through the agency of a resilient sounding board or partition. A shoulder is preferably formed on the interi or of the sound box and against this shoulder operates a gasket which need not necessarily be resilient. The diaphragm rests against this gasket and the second gasket operates against the opposite side of the diaphragm.

Against the second mentioned gasket the outer periphery of the sounding board or partition engages. A cover closes one side of the sound box and is adapted to press against the central portion of the sounding board and places the same under tension, whereby said sounding board is maintained at all times under more or less tension and serves to tightly hold the diaphragm in position, so that the resiliency of the gaskets is not depended upon for this purpose. By

this arrangement a simple, economical and highly efficient sound. box results which is automatically maintained in operation, high efficiency, and does not require the tension hereinbefore referred to as necessitated by the prior constructions.

Features of the invention, other than those specified, will be apparent from the herein- I after detailed description and claims, when read inconjunction with the accompanying drawings.

The accompanying drawings illustrate one practical embodiment of the invention, but the construction therein shown is to be understood as illustrative, only, and not as defining the limits of the invention.

' Figure 1 is a central section of a sound box embodying the present invention; and,

Figure 2 is a central section of the parts shown in Fig. 1, dismantled or separated from one another.

Referring to the drawings, and, more particularly, to Figures 1 and 2, 3 designates the casing of the sound box, which casing is provided with an in-turned flange. Against this flange 4 is seated a gasket 5 which may be of rubber, fibre or any other desirable material and my be either resilient or not, though I prefer that it be non-resilient. This gasket is preferably made quite thin, and. in practice, the gasket may be made from paper. A diaphragm 7' is seated against the gasket 5 and has associatedtherewith any suitable form of stylus 'bar 6, the stylus bar or mounting therefor forming no part of the present invention. A gasket 8 is seated against the opposite side of the diaphragm. and said diaphragm is gripped and held in position between the gaskets 5 and S. The gasket 8 may be in the form of a thin ring of paper. 7

' In accordance with my invention, the partition 12, is provided with a central aperture 13 and is constructed. for radial resiliency and its outer periphery engages with the gasket 9, while it is engaged at its center by the tubular projection 11 through an intermediate washer or gasket 15. In the construction shown, the gasket 15 is preferably held in position against lateral displacement by a plurality of tongues 14 attached to the partition 12, and these tongues engaging with the interior of the washer 15 hold the same in position. The back of the sound box is closed by a cover 9, which may be in the form of a flat plate, but, for the purpose of illustration, is shown in the drawing as dished, so as to obtain proper depth of sound outlet passage with the minimum sound box thickness. About the central portion of the said cover 9, I provide the inwardly projecting wall 11 to engage the partition 12, and the cover 9 is secured to the casing 3 by means of the screws 10. The parts are so proportioned that when the cover 9 is screwed on tight, the partition 12 is flexed or placed under tension and serves, through such extension to force the gasket 8 tightly against the diaphragm and bring about a gripping of the diaphragm between the gaskets 5 and 8. The construction described, when assembled as shown in Figure 1, provides asound chamber intermediate the partition 12 and the diaphragm 7 and "from this sound chamber the sound gains exit through the central aperture .3 of the partition and the sound outlet passage within the tubular portion 11.

In order to leave su'thcient space between the diaphragm 7 and the partition 12, 1 pro vide the folding edge 16, and this folding portion serves to space the partition from the diaphragm andprovides a sound chamber of suitable dimensions. Furthermore,

this folding edge 16 possesses more or less resiliency which, with the natural resiliency of the remainder of the partition, exerts an elastic pressure upon the diaphrai'n.

If desired, th1s folding portion l6'could extend well inwardly towards the center of p the diaphragm. When this is provided for, it is obvious that the size of the diaphragm 'could be greatly reduced, as to effect a proper holding of the diaphragm it is only necessary that the periphery of the diaphragm meet with the periphery of the folding portion 16.

Having thus fully described the invention, what I claim as new and desire to secur by Letters-Patent is:

1. A sound box embodying a casing provided with an interior ledge, a gasket seated on said ledge, adiaphragm seated on the gasket, a second gasket positioned on the opposite side of the diaphragm, a cover cured to the box, and an inherently resilient partition bearing on such second mentioned gasket, engaged by the cover and operated through such engagement to tension the par tition.

2. A sound box embodying a casing provided at one side with an iii-turned flange, a gasket seated against said flange, a diaphragm seated on said gasket, a second g:,a,sket seated against the opposite sideof the diaphragm, a cover secured to the other side of the sound box and a resilient partition clamped under tension between the cover and the second mentioned gasket to engage the gasket with the outer periphery of the partition and to engage the cover near the cen- 'tral portion of the partition, whereby the diaphragm is clamped between the gaskets by the inherent resiliency of the partition.

3. A sound box embodying a casing provided with an interior lalge, a'gasket seated on said ledge, a diaphragm seated on the gasket, and second gasket seated on the to one side of the sound box and having a re-entrant portion engaging with the partition at the central portion thereof for the purpose of placing the partition under tension to'clamp the diaphragm between the gaskets.

i. A sound box embodying a casing provided with an interior lodge, a gasket seated on said ledge, a diaphragmseated on the gasketand a second gasket positioned on the opposite side of the (liaplaigm, in combination with a resilient partition provided at its center with a sound exit aperture and engaging at its outer periphery with the second mentioned gasket, a plate secured to one side of the sound box and prorided with an 'interiorlv projecting tubular portion engaging the center of the partition about the aperture thereof to form a sound exit passage and simultaneously plac the partition under tension for the purpose of rlan'i iiing the diaphragm between the gaskets; V j

5. A sound box embodying a casing pro vided with an interior ledge, a gasket seated on said ledge, a diaphragm seated on the gasket, a second gasket positioned on the opposite side of the diaphragm, a cover secured to the box, and a resilient partition clamped between the cover and the second mentioned gasket under tension and provided at its outer periphery with a rolled portion for spacing the partition from the diaphragm to provide an intermediate sound chamber.

6. A sound box embodying a casing pro vided with an interior ledge, a gasket seated on'said lodge, a diaphragm seated on the gasket, and a second gasket seated on the opposite side of the diaphragm, in combination with a dished resilient partition provided at its out-er periphery with an upwardly and inwardly turned flange engaging, with the second mentioned gasket, and a plate secured to one side oi the sound box and having a re-entrant portion engaging with the partition at thecentral portion thereof, for the our nose of lacing the m .i i i s l tition under tension to clamp 'the'd-iaphragm between the gaskets, the upwardly and inwardly turned flange of the partition ing to space the partition "from the diaphragm and provide an. intermediate sound chamber. 7

7. A sound box including a casing having a removable cover, a diaphragm, an inherently resilient sounding board engaging the diaphragm, and means whereby said. sounding board may beoperated to place the same under tension to exert a holding pressure through such tension on the diaphragm.

8. A sound box including a easlng having aremovable corer, a diaphragm, an inherently resilient sounding board directly operated in the application of the cover to tension said sounding board to secure the diaphragm in position through such tension.

9. A sound box including a casing, a diaphragm therein, a sounding board of inherently resilient material having an edge bearing on the diaphragm, and rigid means cooperating with the casing to engage and tension said sounding board to utilize the same as a resilient holding element 'for the diaphragm.

10. A sound box comprising a casing, a diaphragm arranged therein, an inherently resilient sounding board having edge engagement with the diaphragm, and means to engage and operate the central portion of said sounding board to create a tension therein to increase the pressure of the edge bearing of said sounding board on the diaphragm.

11. A sound box having a casing, a diaphragm mounted therein, an inherently resilient partition at one side of the diaphragm and formed with an opening, and a cover for the casing, said cover having a hollow extension to engage and operate the partition about the opening to create a tension in said partition and thereby provide a resilient tension holding for the diaphragm.

12. A sound box comprising a casing, a diaphragm mounted therein, an inherently resilient partition arranged in the casing and formed with an opening, a cover for the rasing spaced from the partition and having a hollow tubular portion to bear upon and actuate the partition to tension the same when the cover is secured to the easing. whereby to resiliently hold the diato resiliently hold the diaphragm in position.

1 1. A diaphragm securing means for sound boxes. comprising an inherently resilient partition formed with a sound opening and with a pro-formed edge folded back and spaced from the body of the diaphragm.

15. A diaphragm securing means for sound boxes comprising an inherently resilient concavo-conver; partition formed with sound opening and with a holding edge spaced from the body or the diaphragm.

16. A diaphragm securing means for sound boxes comprising a resilient concavoconvex partition formed with a sound openin and with a holding edge, said edge being inturned to space the full circumferential area of the partition from the diaphragm.

17. A diaphragm securing means for sound boxes, comprising a partition formed with a sound opening, and means integral with said partition and arranged about the sound opening to engage and hold a gasket adjacent the sound opening, and a cover plate for the sound box cooperating with the gasket.

18. A diaphragm securing means for sound boxes, comprising a partition adapted to be arranged interiorly of the sound box and formed with a sound opening, and segmental means integral with said partition and arranged about the sound opening to engage and hold a gasket adjacent the sound opening.

19. A sound box including a casing and a cover for one side of the casing, a diaphragm, a concave-convex sounding board, and rigid means projecting inwardly of the cover -tor engaging the sounding board to force the same under tension against the periphery oi? the diaphragm.

520. A sound box including a casing, a cover tor one side thereof, a diaphragm, a sounding board, the periphery of the sound ing board being formed with a curved por tion to provide an independent edge to bear on the diaphragm, and means projecting from the cover for engaging the sounding board to cause said sounding board to engage and hold the diaphragm, said independent edge of the sounding board serving to maintain the sounding board and diaphragm in spaced relation throughout their full area.

21. A sound box including a diaphragm arranged to provide a sound space on one side thereof and a member having integral diaphragm holding means including a preformed edge folded back andispaced throughout from the member inwardly of the wall of the sound box, whereby the sound space is increased beyond the sounding edge of the diaphragm.

In testimony whereof, I have signed my name to this specification.

HAROLD Y. PRENDERGAST. 

